1. Field of the Invention
The present invention relates to a method of manufacturing a toner, a device of manufacturing a toner, and a toner.
2. Description of the Related Art
A developer to be used to develop an electrostatic image in electrophotography, electrostatic recording, electrostatic printing, or the like, for example, once adheres to an image carrier such as an electrostatic latent image supporter on which an electrostatic image is formed, in its development process, then transfers from the electrostatic latent image supporter to a transfer medium such as a transfer paper sheet in a transfer process, and subsequently is fixed on the surface of the paper sheet in a fixation process. In this case, a two-component-type developer composed of a carrier and a toner and a one-component-type developer needing no carrier (a magnetic toner or a non-magnetic toner) have been known as developers for developing an electrostatic image formed on a latent image holding surface.
Conventionally, a so-called grinded toner provided by melting and kneading a toner binder such as a styrene-type resin or a polyester-type resin, a coloring agent, etc., and milling it has been widely used as a dry-type toner to be used for electrophotography, electrostatic recording, electrostatic printing, or the like.
Recently, a method for manufacturing a toner based on a suspension polymerization method or an emulsification polymerization aggregation method, a so-called polymerization-type toner has been examined. In addition, a manufacturing method involving volume shrinkage, referred to as a polymer dissolution suspension method has also been examined (see Japanese Patent Application Publication No. H07-152202). This method is to disperse and dissolve toner materials in a volatile solvent such as a low-boiling-point organic solvent, then emulsify it in an aqueous medium in which a dispersing agent is present, so as to form into a liquid drop, and subsequently remove the volatile solvent. This method is different from a suspension polymerization method and an emulsification polymerization aggregation method in that there is a wide versatility in usable resins, and in particular, excellent in that it may be possible to use a polyester resin useful for a full-color process in which a transparency or a smoothness of an image portion after its fixation is required.
However, it has been known that, for example, a disadvantage may be caused such that a dispersing agent degrading a toner charging characteristic remains on a toner surface so as to degrade its environmental stability, or a enormous amount of washing water may be required for eliminating it, in the above-mentioned polymerization-type toner, because it is based on the premise that a dispersing agent is used in an aqueous medium, and it is not necessarily a satisfactory manufacturing method.
Meanwhile, a spray drying method has been known as a method for manufacturing a toner using no aqueous medium conventionally (see Japanese Examined Patent Application Publication No. S57-201248). Because this is to form into a fine particle, to eject, and to dry, a melt of toner components or a liquid in toner component liquid is dissolved, using various atomizers, to obtain a particle, no disadvantage may be caused by using an aqueous medium.
However, a particle obtained by a conventional spray particle-manufacturing method is comparatively coarse and large and its particle size distribution is also wide, which may accordingly cause degradation of the intrinsic characteristics of a toner.
Then, for a toner manufacturing method replacing it, a method and device for forming a fine liquid drop utilizing a piezoelectric pulse and further drying and solidifying it to provide a toner have been proposed (see Japanese Patent No. 3786034). Furthermore, a manufacturing method for forming a fine liquid particle utilizing thermal expansion in a nozzle and further drying and solidifying it to provide a toner has also been proposed (see Japanese Patent No. 3786035).
However, it may merely be possible to conduct liquid drop ejection from one nozzle using one piezoelectric body and the number of liquid drops which can be ejected in a unit of time may be small, in the methods and device for manufacturing a toner as disclosed in the aforementioned Japanese Patent No. 3786034 and Japanese Patent No. 3786035, whereby there may be a problem of low productivity.
Then, it has been proposed that a toner particle is provided by vibrating a nozzle due to stretching of a piezoelectric body as vibration generation means so as to eject a liquid drop of a toner composition fluid from the nozzle at a constant frequency and solidifying that liquid as disclosed in Japanese Patent Application Publication No. 2006-293320, and an ejection member having an ejection port and vibration applying means for applying vibration to that ejection member at a predetermined frequency are included wherein a toner particle is manufactured by vibrating the ejection member as a vibration member so as to eject a liquid drop from the ejection port and drying and solidifying the liquid drop as disclosed in Japanese Patent Application Publication No. 2006-297325.
However, in a configuration such that a piezoelectric body is put close to the peripheral portion of a nozzle as described above and the nozzle is vibrated by means of stretching of the piezoelectric body so as to form into a liquid drop and eject a toner composition liquid, vibration is merely generated at a nozzle region in a region corresponding to an aperture portion of the piezoelectric body, and accordingly, it may be impossible to obtain a large deformation of the nozzle. That is, when a toner composition liquid with a high viscosity (for example, 10 mPa·s) in which a large quantity of solid content is dispersed is ejected, clogging may occur readily and the configuration is yet insufficient in order to manufacture a toner stably and efficiently.
Then, the inventors have actively examined a configuration using vibration generating means for vibrating a thin film forming a nozzle via a toner composition liquid, and as a result, it was confirmed that it might be possible to obtain sufficient vibration due to such a configuration, but, on the other hand, this configuration encountered a new problem such that irregularity of vibration of a thin film forming a nozzle might be caused by means of resonance of a toner composition liquid and irregularity of a liquid drop size (ultimately, a toner size) might be caused.